sys_socket.c

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/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)sys_socket.c        8.1 (Berkeley) 6/10/93
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/aio.h>
#include <sys/domain.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/sigio.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/filio.h>                  /* XXX */
#include <sys/sockio.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/sysproto.h>
#include <sys/taskqueue.h>
#include <sys/uio.h>
#include <sys/ucred.h>
#include <sys/un.h>
#include <sys/unpcb.h>
#include <sys/user.h>
 
#include <net/if.h>
#include <net/if_var.h>
#include <net/route.h>
#include <net/vnet.h>
 
#include <netinet/in.h>
#include <netinet/in_pcb.h>
 
#include <security/mac/mac_framework.h>
 
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_extern.h>
#include <vm/vm_map.h>
 
static SYSCTL_NODE(_kern_ipc, OID_AUTO, aio, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
    "socket AIO stats");
 
static int empty_results;
SYSCTL_INT(_kern_ipc_aio, OID_AUTO, empty_results, CTLFLAG_RD, &empty_results,
    0, "socket operation returned EAGAIN");
 
static int empty_retries;
SYSCTL_INT(_kern_ipc_aio, OID_AUTO, empty_retries, CTLFLAG_RD, &empty_retries,
    0, "socket operation retries");
 
static fo_rdwr_t soo_read;
static fo_rdwr_t soo_write;
static fo_ioctl_t soo_ioctl;
static fo_poll_t soo_poll;
extern fo_kqfilter_t soo_kqfilter;
static fo_stat_t soo_stat;
static fo_close_t soo_close;
static fo_fill_kinfo_t soo_fill_kinfo;
static fo_aio_queue_t soo_aio_queue;
 
static void     soo_aio_cancel(struct kaiocb *job);
 
struct fileops  socketops = {
        .fo_read = soo_read,
        .fo_write = soo_write,
        .fo_truncate = invfo_truncate,
        .fo_ioctl = soo_ioctl,
        .fo_poll = soo_poll,
        .fo_kqfilter = soo_kqfilter,
        .fo_stat = soo_stat,
        .fo_close = soo_close,
        .fo_chmod = invfo_chmod,
        .fo_chown = invfo_chown,
        .fo_sendfile = invfo_sendfile,
        .fo_fill_kinfo = soo_fill_kinfo,
        .fo_aio_queue = soo_aio_queue,
        .fo_flags = DFLAG_PASSABLE
};
 
static int
soo_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
    int flags, struct thread *td)
{
        struct socket *so = fp->f_data;
        int error;
 
#ifdef MAC
        error = mac_socket_check_receive(active_cred, so);
        if (error)
                return (error);
#endif
        error = soreceive(so, 0, uio, 0, 0, 0);
        return (error);
}
 
static int
soo_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
    int flags, struct thread *td)
{
        struct socket *so = fp->f_data;
        int error;
 
#ifdef MAC
        error = mac_socket_check_send(active_cred, so);
        if (error)
                return (error);
#endif
        error = sosend(so, 0, uio, 0, 0, 0, uio->uio_td);
        if (error == EPIPE && (so->so_options & SO_NOSIGPIPE) == 0) {
                PROC_LOCK(uio->uio_td->td_proc);
                tdsignal(uio->uio_td, SIGPIPE);
                PROC_UNLOCK(uio->uio_td->td_proc);
        }
        return (error);
}
 
static int
soo_ioctl(struct file *fp, u_long cmd, void *data, struct ucred *active_cred,
    struct thread *td)
{
        struct socket *so = fp->f_data;
        int error = 0;
 
        switch (cmd) {
        case FIONBIO:
                SOCK_LOCK(so);
                if (*(int *)data)
                        so->so_state |= SS_NBIO;
                else
                        so->so_state &= ~SS_NBIO;
                SOCK_UNLOCK(so);
                break;
 
        case FIOASYNC:
                if (*(int *)data) {
                        SOCK_LOCK(so);
                        so->so_state |= SS_ASYNC;
                        if (SOLISTENING(so)) {
                                so->sol_sbrcv_flags |= SB_ASYNC;
                                so->sol_sbsnd_flags |= SB_ASYNC;
                        } else {
                                SOCKBUF_LOCK(&so->so_rcv);
                                so->so_rcv.sb_flags |= SB_ASYNC;
                                SOCKBUF_UNLOCK(&so->so_rcv);
                                SOCKBUF_LOCK(&so->so_snd);
                                so->so_snd.sb_flags |= SB_ASYNC;
                                SOCKBUF_UNLOCK(&so->so_snd);
                        }
                        SOCK_UNLOCK(so);
                } else {
                        SOCK_LOCK(so);
                        so->so_state &= ~SS_ASYNC;
                        if (SOLISTENING(so)) {
                                so->sol_sbrcv_flags &= ~SB_ASYNC;
                                so->sol_sbsnd_flags &= ~SB_ASYNC;
                        } else {
                                SOCKBUF_LOCK(&so->so_rcv);
                                so->so_rcv.sb_flags &= ~SB_ASYNC;
                                SOCKBUF_UNLOCK(&so->so_rcv);
                                SOCKBUF_LOCK(&so->so_snd);
                                so->so_snd.sb_flags &= ~SB_ASYNC;
                                SOCKBUF_UNLOCK(&so->so_snd);
                        }
                        SOCK_UNLOCK(so);
                }
                break;
 
        case FIONREAD:
                SOCK_RECVBUF_LOCK(so);
                if (SOLISTENING(so)) {
                        error = EINVAL;
                } else {
                        *(int *)data = sbavail(&so->so_rcv) - so->so_rcv.sb_ctl;
                }
                SOCK_RECVBUF_UNLOCK(so);
                break;
 
        case FIONWRITE:
                /* Unlocked read. */
                if (SOLISTENING(so)) {
                        error = EINVAL;
                } else {
                        *(int *)data = sbavail(&so->so_snd);
                }
                break;
 
        case FIONSPACE:
                /* Unlocked read. */
                if (SOLISTENING(so)) {
                        error = EINVAL;
                } else {
                        if ((so->so_snd.sb_hiwat < sbused(&so->so_snd)) ||
                            (so->so_snd.sb_mbmax < so->so_snd.sb_mbcnt)) {
                                *(int *)data = 0;
                        } else {
                                *(int *)data = sbspace(&so->so_snd);
                        }
                }
                break;
 
        case FIOSETOWN:
                error = fsetown(*(int *)data, &so->so_sigio);
                break;
 
        case FIOGETOWN:
                *(int *)data = fgetown(&so->so_sigio);
                break;
 
        case SIOCSPGRP:
                error = fsetown(-(*(int *)data), &so->so_sigio);
                break;
 
        case SIOCGPGRP:
                *(int *)data = -fgetown(&so->so_sigio);
                break;
 
        case SIOCATMARK:
                /* Unlocked read. */
                if (SOLISTENING(so)) {
                        error = EINVAL;
                } else {
                        *(int *)data = (so->so_rcv.sb_state & SBS_RCVATMARK) != 0;
                }
                break;
        default:
                /*
                 * Interface/routing/protocol specific ioctls: interface and
                 * routing ioctls should have a different entry since a
                 * socket is unnecessary.
                 */
                if (IOCGROUP(cmd) == 'i')
                        error = ifioctl(so, cmd, data, td);
                else if (IOCGROUP(cmd) == 'r') {
                        CURVNET_SET(so->so_vnet);
                        error = rtioctl_fib(cmd, data, so->so_fibnum);
                        CURVNET_RESTORE();
                } else {
                        CURVNET_SET(so->so_vnet);
                        error = ((*so->so_proto->pr_usrreqs->pru_control)
                            (so, cmd, data, 0, td));
                        CURVNET_RESTORE();
                }
                break;
        }
        return (error);
}
 
static int
soo_poll(struct file *fp, int events, struct ucred *active_cred,
    struct thread *td)
{
        struct socket *so = fp->f_data;
#ifdef MAC
        int error;
 
        error = mac_socket_check_poll(active_cred, so);
        if (error)
                return (error);
#endif
        return (sopoll(so, events, fp->f_cred, td));
}
 
static int
soo_stat(struct file *fp, struct stat *ub, struct ucred *active_cred)
{
        struct socket *so = fp->f_data;
        int error;
 
        bzero((caddr_t)ub, sizeof (*ub));
        ub->st_mode = S_IFSOCK;
#ifdef MAC
        error = mac_socket_check_stat(active_cred, so);
        if (error)
                return (error);
#endif
        SOCK_LOCK(so);
        if (!SOLISTENING(so)) {
                struct sockbuf *sb;
 
                /*
                 * If SBS_CANTRCVMORE is set, but there's still data left
                 * in the receive buffer, the socket is still readable.
                 */
                sb = &so->so_rcv;
                SOCKBUF_LOCK(sb);
                if ((sb->sb_state & SBS_CANTRCVMORE) == 0 || sbavail(sb))
                        ub->st_mode |= S_IRUSR | S_IRGRP | S_IROTH;
                ub->st_size = sbavail(sb) - sb->sb_ctl;
                SOCKBUF_UNLOCK(sb);
 
                sb = &so->so_snd;
                SOCKBUF_LOCK(sb);
                if ((sb->sb_state & SBS_CANTSENDMORE) == 0)
                        ub->st_mode |= S_IWUSR | S_IWGRP | S_IWOTH;
                SOCKBUF_UNLOCK(sb);
        }
        ub->st_uid = so->so_cred->cr_uid;
        ub->st_gid = so->so_cred->cr_gid;
        error = so->so_proto->pr_usrreqs->pru_sense(so, ub);
        SOCK_UNLOCK(so);
        return (error);
}
 
/*
 * API socket close on file pointer.  We call soclose() to close the socket
 * (including initiating closing protocols).  soclose() will sorele() the
 * file reference but the actual socket will not go away until the socket's
 * ref count hits 0.
 */
static int
soo_close(struct file *fp, struct thread *td)
{
        int error = 0;
        struct socket *so;
 
        so = fp->f_data;
        fp->f_ops = &badfileops;
        fp->f_data = NULL;
 
        if (so)
                error = soclose(so);
        return (error);
}
 
static int
soo_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
{
        struct sockaddr *sa;
        struct inpcb *inpcb;
        struct unpcb *unpcb;
        struct socket *so;
        int error;
 
        kif->kf_type = KF_TYPE_SOCKET;
        so = fp->f_data;
        CURVNET_SET(so->so_vnet);
        kif->kf_un.kf_sock.kf_sock_domain0 =
            so->so_proto->pr_domain->dom_family;
        kif->kf_un.kf_sock.kf_sock_type0 = so->so_type;
        kif->kf_un.kf_sock.kf_sock_protocol0 = so->so_proto->pr_protocol;
        kif->kf_un.kf_sock.kf_sock_pcb = (uintptr_t)so->so_pcb;
        switch (kif->kf_un.kf_sock.kf_sock_domain0) {
        case AF_INET:
        case AF_INET6:
                if (kif->kf_un.kf_sock.kf_sock_protocol0 == IPPROTO_TCP) {
                        if (so->so_pcb != NULL) {
                                inpcb = (struct inpcb *)(so->so_pcb);
                                kif->kf_un.kf_sock.kf_sock_inpcb =
                                    (uintptr_t)inpcb->inp_ppcb;
                                kif->kf_un.kf_sock.kf_sock_sendq =
                                    sbused(&so->so_snd);
                                kif->kf_un.kf_sock.kf_sock_recvq =
                                    sbused(&so->so_rcv);
                        }
                }
                break;
        case AF_UNIX:
                if (so->so_pcb != NULL) {
                        unpcb = (struct unpcb *)(so->so_pcb);
                        if (unpcb->unp_conn) {
                                kif->kf_un.kf_sock.kf_sock_unpconn =
                                    (uintptr_t)unpcb->unp_conn;
                                kif->kf_un.kf_sock.kf_sock_rcv_sb_state =
                                    so->so_rcv.sb_state;
                                kif->kf_un.kf_sock.kf_sock_snd_sb_state =
                                    so->so_snd.sb_state;
                                kif->kf_un.kf_sock.kf_sock_sendq =
                                    sbused(&so->so_snd);
                                kif->kf_un.kf_sock.kf_sock_recvq =
                                    sbused(&so->so_rcv);
                        }
                }
                break;
        }
        error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
        if (error == 0 &&
            sa->sa_len <= sizeof(kif->kf_un.kf_sock.kf_sa_local)) {
                bcopy(sa, &kif->kf_un.kf_sock.kf_sa_local, sa->sa_len);
                free(sa, M_SONAME);
        }
        error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
        if (error == 0 &&
            sa->sa_len <= sizeof(kif->kf_un.kf_sock.kf_sa_peer)) {
                bcopy(sa, &kif->kf_un.kf_sock.kf_sa_peer, sa->sa_len);
                free(sa, M_SONAME);
        }
        strncpy(kif->kf_path, so->so_proto->pr_domain->dom_name,
            sizeof(kif->kf_path));
        CURVNET_RESTORE();
        return (0);     
}
 
/*
 * Use the 'backend3' field in AIO jobs to store the amount of data
 * completed by the AIO job so far.
 */
#define aio_done        backend3
 
static STAILQ_HEAD(, task) soaio_jobs;
static struct mtx soaio_jobs_lock;
static struct task soaio_kproc_task;
static int soaio_starting, soaio_idle, soaio_queued;
static struct unrhdr *soaio_kproc_unr;
 
static int soaio_max_procs = MAX_AIO_PROCS;
SYSCTL_INT(_kern_ipc_aio, OID_AUTO, max_procs, CTLFLAG_RW, &soaio_max_procs, 0,
    "Maximum number of kernel processes to use for async socket IO");
 
static int soaio_num_procs;
SYSCTL_INT(_kern_ipc_aio, OID_AUTO, num_procs, CTLFLAG_RD, &soaio_num_procs, 0,
    "Number of active kernel processes for async socket IO");
 
static int soaio_target_procs = TARGET_AIO_PROCS;
SYSCTL_INT(_kern_ipc_aio, OID_AUTO, target_procs, CTLFLAG_RD,
    &soaio_target_procs, 0,
    "Preferred number of ready kernel processes for async socket IO");
 
static int soaio_lifetime;
SYSCTL_INT(_kern_ipc_aio, OID_AUTO, lifetime, CTLFLAG_RW, &soaio_lifetime, 0,
    "Maximum lifetime for idle aiod");
 
static void
soaio_kproc_loop(void *arg)
{
        struct proc *p;
        struct vmspace *myvm;
        struct task *task;
        int error, id, pending;
 
        id = (intptr_t)arg;
 
        /*
         * Grab an extra reference on the daemon's vmspace so that it
         * doesn't get freed by jobs that switch to a different
         * vmspace.
         */
        p = curproc;
        myvm = vmspace_acquire_ref(p);
 
        mtx_lock(&soaio_jobs_lock);
        MPASS(soaio_starting > 0);
        soaio_starting--;
        for (;;) {
                while (!STAILQ_EMPTY(&soaio_jobs)) {
                        task = STAILQ_FIRST(&soaio_jobs);
                        STAILQ_REMOVE_HEAD(&soaio_jobs, ta_link);
                        soaio_queued--;
                        pending = task->ta_pending;
                        task->ta_pending = 0;
                        mtx_unlock(&soaio_jobs_lock);
 
                        task->ta_func(task->ta_context, pending);
 
                        mtx_lock(&soaio_jobs_lock);
                }
                MPASS(soaio_queued == 0);
 
                if (p->p_vmspace != myvm) {
                        mtx_unlock(&soaio_jobs_lock);
                        vmspace_switch_aio(myvm);
                        mtx_lock(&soaio_jobs_lock);
                        continue;
                }
 
                soaio_idle++;
                error = mtx_sleep(&soaio_idle, &soaio_jobs_lock, 0, "-",
                    soaio_lifetime);
                soaio_idle--;
                if (error == EWOULDBLOCK && STAILQ_EMPTY(&soaio_jobs) &&
                    soaio_num_procs > soaio_target_procs)
                        break;
        }
        soaio_num_procs--;
        mtx_unlock(&soaio_jobs_lock);
        free_unr(soaio_kproc_unr, id);
        kproc_exit(0);
}
 
static void
soaio_kproc_create(void *context, int pending)
{
        struct proc *p;
        int error, id;
 
        mtx_lock(&soaio_jobs_lock);
        for (;;) {
                if (soaio_num_procs < soaio_target_procs) {
                        /* Must create */
                } else if (soaio_num_procs >= soaio_max_procs) {
                        /*
                         * Hit the limit on kernel processes, don't
                         * create another one.
                         */
                        break;
                } else if (soaio_queued <= soaio_idle + soaio_starting) {
                        /*
                         * No more AIO jobs waiting for a process to be
                         * created, so stop.
                         */
                        break;
                }
                soaio_starting++;
                mtx_unlock(&soaio_jobs_lock);
 
                id = alloc_unr(soaio_kproc_unr);
                error = kproc_create(soaio_kproc_loop, (void *)(intptr_t)id,
                    &p, 0, 0, "soaiod%d", id);
                if (error != 0) {
                        free_unr(soaio_kproc_unr, id);
                        mtx_lock(&soaio_jobs_lock);
                        soaio_starting--;
                        break;
                }
 
                mtx_lock(&soaio_jobs_lock);
                soaio_num_procs++;
        }
        mtx_unlock(&soaio_jobs_lock);
}
 
void
soaio_enqueue(struct task *task)
{
 
        mtx_lock(&soaio_jobs_lock);
        MPASS(task->ta_pending == 0);
        task->ta_pending++;
        STAILQ_INSERT_TAIL(&soaio_jobs, task, ta_link);
        soaio_queued++;
        if (soaio_queued <= soaio_idle)
                wakeup_one(&soaio_idle);
        else if (soaio_num_procs < soaio_max_procs)
                taskqueue_enqueue(taskqueue_thread, &soaio_kproc_task);
        mtx_unlock(&soaio_jobs_lock);
}
 
static void
soaio_init(void)
{
 
        soaio_lifetime = AIOD_LIFETIME_DEFAULT;
        STAILQ_INIT(&soaio_jobs);
        mtx_init(&soaio_jobs_lock, "soaio jobs", NULL, MTX_DEF);
        soaio_kproc_unr = new_unrhdr(1, INT_MAX, NULL);
        TASK_INIT(&soaio_kproc_task, 0, soaio_kproc_create, NULL);
}
SYSINIT(soaio, SI_SUB_VFS, SI_ORDER_ANY, soaio_init, NULL);
 
static __inline int
soaio_ready(struct socket *so, struct sockbuf *sb)
{
        return (sb == &so->so_rcv ? soreadable(so) : sowriteable(so));
}
 
static void
soaio_process_job(struct socket *so, struct sockbuf *sb, struct kaiocb *job)
{
        struct ucred *td_savedcred;
        struct thread *td;
        struct file *fp;
        size_t cnt, done, job_total_nbytes __diagused;
        long ru_before;
        int error, flags;
 
        SOCKBUF_UNLOCK(sb);
        aio_switch_vmspace(job);
        td = curthread;
        fp = job->fd_file;
retry:
        td_savedcred = td->td_ucred;
        td->td_ucred = job->cred;
 
        job_total_nbytes = job->uiop->uio_resid + job->aio_done;
        done = job->aio_done;
        cnt = job->uiop->uio_resid;
        job->uiop->uio_offset = 0;
        job->uiop->uio_td = td;
        flags = MSG_NBIO;
 
        /*
         * For resource usage accounting, only count a completed request
         * as a single message to avoid counting multiple calls to
         * sosend/soreceive on a blocking socket.
         */
 
        if (sb == &so->so_rcv) {
                ru_before = td->td_ru.ru_msgrcv;
#ifdef MAC
                error = mac_socket_check_receive(fp->f_cred, so);
                if (error == 0)
 
#endif
                        error = soreceive(so, NULL, job->uiop, NULL, NULL,
                            &flags);
                if (td->td_ru.ru_msgrcv != ru_before)
                        job->msgrcv = 1;
        } else {
                if (!TAILQ_EMPTY(&sb->sb_aiojobq))
                        flags |= MSG_MORETOCOME;
                ru_before = td->td_ru.ru_msgsnd;
#ifdef MAC
                error = mac_socket_check_send(fp->f_cred, so);
                if (error == 0)
#endif
                        error = sosend(so, NULL, job->uiop, NULL, NULL, flags,
                            td);
                if (td->td_ru.ru_msgsnd != ru_before)
                        job->msgsnd = 1;
                if (error == EPIPE && (so->so_options & SO_NOSIGPIPE) == 0) {
                        PROC_LOCK(job->userproc);
                        kern_psignal(job->userproc, SIGPIPE);
                        PROC_UNLOCK(job->userproc);
                }
        }
 
        done += cnt - job->uiop->uio_resid;
        job->aio_done = done;
        td->td_ucred = td_savedcred;
 
        if (error == EWOULDBLOCK) {
                /*
                 * The request was either partially completed or not
                 * completed at all due to racing with a read() or
                 * write() on the socket.  If the socket is
                 * non-blocking, return with any partial completion.
                 * If the socket is blocking or if no progress has
                 * been made, requeue this request at the head of the
                 * queue to try again when the socket is ready.
                 */
                MPASS(done != job_total_nbytes);
                SOCKBUF_LOCK(sb);
                if (done == 0 || !(so->so_state & SS_NBIO)) {
                        empty_results++;
                        if (soaio_ready(so, sb)) {
                                empty_retries++;
                                SOCKBUF_UNLOCK(sb);
                                goto retry;
                        }
                        
                        if (!aio_set_cancel_function(job, soo_aio_cancel)) {
                                SOCKBUF_UNLOCK(sb);
                                if (done != 0)
                                        aio_complete(job, done, 0);
                                else
                                        aio_cancel(job);
                                SOCKBUF_LOCK(sb);
                        } else {
                                TAILQ_INSERT_HEAD(&sb->sb_aiojobq, job, list);
                        }
                        return;
                }
                SOCKBUF_UNLOCK(sb);
        }               
        if (done != 0 && (error == ERESTART || error == EINTR ||
            error == EWOULDBLOCK))
                error = 0;
        if (error)
                aio_complete(job, -1, error);
        else
                aio_complete(job, done, 0);
        SOCKBUF_LOCK(sb);
}
 
static void
soaio_process_sb(struct socket *so, struct sockbuf *sb)
{
        struct kaiocb *job;
 
        CURVNET_SET(so->so_vnet);
        SOCKBUF_LOCK(sb);
        while (!TAILQ_EMPTY(&sb->sb_aiojobq) && soaio_ready(so, sb)) {
                job = TAILQ_FIRST(&sb->sb_aiojobq);
                TAILQ_REMOVE(&sb->sb_aiojobq, job, list);
                if (!aio_clear_cancel_function(job))
                        continue;
 
                soaio_process_job(so, sb, job);
        }
 
        /*
         * If there are still pending requests, the socket must not be
         * ready so set SB_AIO to request a wakeup when the socket
         * becomes ready.
         */
        if (!TAILQ_EMPTY(&sb->sb_aiojobq))
                sb->sb_flags |= SB_AIO;
        sb->sb_flags &= ~SB_AIO_RUNNING;
        SOCKBUF_UNLOCK(sb);
 
        sorele(so);
        CURVNET_RESTORE();
}
 
void
soaio_rcv(void *context, int pending)
{
        struct socket *so;
 
        so = context;
        soaio_process_sb(so, &so->so_rcv);
}
 
void
soaio_snd(void *context, int pending)
{
        struct socket *so;
 
        so = context;
        soaio_process_sb(so, &so->so_snd);
}
 
void
sowakeup_aio(struct socket *so, struct sockbuf *sb)
{
 
        SOCKBUF_LOCK_ASSERT(sb);
        sb->sb_flags &= ~SB_AIO;
        if (sb->sb_flags & SB_AIO_RUNNING)
                return;
        sb->sb_flags |= SB_AIO_RUNNING;
        soref(so);
        soaio_enqueue(&sb->sb_aiotask);
}
 
static void
soo_aio_cancel(struct kaiocb *job)
{
        struct socket *so;
        struct sockbuf *sb;
        long done;
        int opcode;
 
        so = job->fd_file->f_data;
        opcode = job->uaiocb.aio_lio_opcode;
        if (opcode & LIO_READ)
                sb = &so->so_rcv;
        else {
                MPASS(opcode & LIO_WRITE);
                sb = &so->so_snd;
        }
 
        SOCKBUF_LOCK(sb);
        if (!aio_cancel_cleared(job))
                TAILQ_REMOVE(&sb->sb_aiojobq, job, list);
        if (TAILQ_EMPTY(&sb->sb_aiojobq))
                sb->sb_flags &= ~SB_AIO;
        SOCKBUF_UNLOCK(sb);
 
        done = job->aio_done;
        if (done != 0)
                aio_complete(job, done, 0);
        else
                aio_cancel(job);
}
 
static int
soo_aio_queue(struct file *fp, struct kaiocb *job)
{
        struct socket *so;
        struct sockbuf *sb;
        int error;
 
        so = fp->f_data;
        error = (*so->so_proto->pr_usrreqs->pru_aio_queue)(so, job);
        if (error == 0)
                return (0);
 
        /* Lock through the socket, since this may be a listening socket. */
        switch (job->uaiocb.aio_lio_opcode & (LIO_WRITE | LIO_READ)) {
        case LIO_READ:
                sb = &so->so_rcv;
                SOCK_RECVBUF_LOCK(so);
                break;
        case LIO_WRITE:
                sb = &so->so_snd;
                SOCK_SENDBUF_LOCK(so);
                break;
        default:
                return (EINVAL);
        }
 
        if (SOLISTENING(so)) {
                if (sb == &so->so_rcv)
                        SOCK_RECVBUF_UNLOCK(so);
                else
                        SOCK_SENDBUF_UNLOCK(so);
                return (EINVAL);
        }
 
        if (!aio_set_cancel_function(job, soo_aio_cancel))
                panic("new job was cancelled");
        TAILQ_INSERT_TAIL(&sb->sb_aiojobq, job, list);
        if (!(sb->sb_flags & SB_AIO_RUNNING)) {
                if (soaio_ready(so, sb))
                        sowakeup_aio(so, sb);
                else
                        sb->sb_flags |= SB_AIO;
        }
        SOCKBUF_UNLOCK(sb);
        return (0);
}